Programmed and altruistic ageing

Abstract

Ageing is widely believed to be a non-adaptive process that results from a decline in the force of natural selection. However, recent studies in Saccharomyces cerevisiae are consistent with the existence of a programme of altruistic ageing and death. We suggest that the similarities between the molecular pathways that regulate ageing in yeast, worms, flies and mice, together with evidence that is consistent with programmed death in salmon and other organisms, raise the possibility that programmed ageing or death can also occur in higher eukaryotes.

Apoptosis in developmental and repair-related human tooth remodeling: A view from the inside

“…These changes contribute to the elimination of an important percentage of odontoblasts by apoptosis at the beginning of secondary dentin formation. This is in accordance with numerous studies showing that aging is accompanied by a general decline of physiological function and significant increase of apoptosis [3,23,27].…”

“…Apoptosis is a genetically regulated process of cell elimination and plays fundamental roles in both morphogenesis and pathogenesis of all multicellular organisms [23]. During odontogenesis, apoptosis regulates the cell number by eliminating cells that have already achieved their genetic program, thus controlling the pattern, shape and size of the teeth [7,8,24].…”

Mitochondrial factors with dual roles in death and survival

“…Recently, yeast have joined the ranks of higher organisms as an aging model because genes that determine lifespan in worms, flies and mammals were found to regulate longevity in stationary phase yeast (Fabrizio et al, 2005). Stationary phase yeast are suggested to better reflect the cellular events in metazoans, rather than log phase yeast, which arguably better reflect the characteristics of tumors and of mammalian cell lines (Longo et al, 2005). Interestingly, some genes that promote replicative lifespan of log phase yeast, such as Sir2 (ortholog of mammalian Sirt1), have the opposite effect on the lifespan of stationary phase yeast (Rine, 2005).…”

Aging mechanism as the “down side” of adaptation: A network approach

“…Kirkwood (2005); de Magalhaes (2005)). Free radicals formed during metabolism do cause damage to many parts of the cells (see Balaban et al (2005); Kirkwood (2005)) but a fundamental question remains whether such random damage is the primary cause of aging (Longo et al, 2005;de Magalhaes, 2005). The universality of the snescent phenotype within and across species could argue against it: though many factors point away from the existence of an actual aging "program" (extensively reviewed in Kirkwood (2005)), aging of biological organisms is still a recognizable developmental stage, as is e.g.…”